As millions of fans of the hit show tuned in, they found that Jack Pearson, the beloved character played by Milo Ventimiglia, isn't killed in the fire that burned down his house. Instead, death came to the beloved TV dad in the form of cardiac arrest caused by smoke inhalation.

"You have got smoke in your lungs, so your lungs are not getting oxygen normally, so, your heart is not getting blood," he said. "Then you got the running around, which makes your heart beat faster, which means it needs more oxygen."

Meanwhile, many nurses are taking to social media to explain that the character didn't really have to die.

"Why does he not have oxygen on?" tweeted one.

"They could've saved Jack," said another.

Dr. Oz said that in this day and age, the prospect of survival is much more likely.

"Now, if you were at the hospital we would put you on a monitor immediately and give you oxygen and we can do things really quickly that could change your life course," he said of today's hospitals.

Dr. Oz also has advice for anyone who may have suffered from smoke inhalation.

"You are going to go to the hospital anyway because smoke inhalation can do all toxic things to your lungs," he said. "It is not just the heat — the chemicals released by all the synthetic materials we have in our homes that can damage the lung immediately and long term."